Sensitive Indicators in the Detection of Coal Workers Pneumoconiosis

摘要

Twenty retired West Virginia coal miners, who presented with respiratory symptoms or radiological changes consistent with coal workers' pneumoconiosis (CWP), participated in a study to identify changes in pulmonary function which occur on exposure to coal dust and to develop improved methods for the early detection of CWP. They underwent a comprehensive series of studies to assess their medical, physiological, and biochemical status. All the miners were life-long non-smokers with a mean age of 58.5 years and an average of 34.1 years' exposure to coal dust. All had dyspnea on exertion, but physical examination showed only minor abnormalities. Chest x rays showed varying degrees of impairment, ranging from normal to complicated CWP. Significant pulmonary impairment was found at the level of the small airways of the lung in all miners, even in the presence of normal chest x rays. This impairment was characterized by a nonuniform distribution of ventilation (Kr-81m scans); abnormal gas exchange manifested by reduced arterial oxygen tensions and increased alveolar-arterial oxygen gradients, but with reduced steady-state CO diffusing capacity at rest discovered in only four miners; and obstruction to air flow in the small airways. In contrast, conventional spirometric measurements were within the predicted normal limits. A mean ventilation nonuniformity index of 0.179 +- 0.027 demonstrated that V/V/sub a/ for the miners was more nonuniform than that of six normal volunteers who had an index of 0.149 +- 0.003. (ERA citation 06:027761)